How large is it? There are thousands of black bugs with pincers of all sizes and shapes, some are harmless and some are not. There are some great books in the library and some great entomology resources online to help you identify what it is.
Many black bugs with pincers are from the beetle family. For instance the giant stag beetle is black and has pincers. The scarites subterraneus is also a black beetle with pincers. Another very common bug that is black with pincers is the earwig. They are a dark blackish brown bug with pincers.
Without knowing more, it will be impossible to completely identify the insect in question. However, I would assume it would be some type of beetle. See if it has 6 legs and its back is split into 2 wings or wing covers.